The big change from the first course is the elimination of the Hogshead Climb from the 50K. You miss out on probably the best road descent of the 100K with this change, but the upside is you don't get the 20-30 minutes of climbing that may accompany the ascent on the 100K course that is often a major decision maker in the long race? What do I mean? Hogshead either makes you or, seemingly more often, breaks you.